Electric irradiator



Dec. 24, 1940.

A, STAHN ET AL ELE'GTRIC IRRADIATOR Patented Dec. 24, 1940 PATENT OFFICE ELECTRIC IRRADIATOR Albert rStalin and Theodor Bornemann,

Hanover, Germany f Application October 8, 1937, Serial No. 168.100

In Germany June 4, 1935 2 Claims.

Our invention relates to electric irradiators.

It is an object of our invention to provide a preferably portable electric irradiator which is ,particularly suitable for therapeutic purposes.

To this end, we use electrodes designed for a minimum current density of 0.26 amp. per square millimetre of electrode cross-sectional area, and we arrange a core in each electrode of such cornposition that a spectrum like the suns is produced. 'I'he core may be of pure metal, or metal oxide, or a metal salt, or of a combination ofany two, or all, of the said substances. According to our invention, the two electrodes are arranged to include an acute angle, and one of them may be parallel to, and preferably at a short distance from, the optical axis of a reflector. Electrodes of the type referred to are old in this art, and it has also been proposed to operate them, by way of investigation, with current densities of the order aforesaid. However, in the apparatus employed for such investigations, the electrodes are aligned axially and the arc burns in a closed-up arc chamber.

In our radiator, on the other hand, atmospheric ,y oxygen is freely admitted to the arc.

In order to obtain a burning period of adequate duration with axially aligned electrodes whose arc is not enclosed in an arc chamber, an automatic electrode feeding mechanism would be required .which would not only increase the cost of the irradiator but would also render it unsuitable for operation by unskilled persons. We overcome these dilllculties by arranging the-highly loaded--electrodes at an acute angle to each other. In this manner, adequate burning periods are obtained without the automatic feeding mechanism referred to, i. e., with the electrodes being stationary during burning.

As compared withA electrodes arranged in parallel relation to, and at a short distance from, each other, our angularly arranged electrodes have the advantage that the arc is extinguished automatically after a predetermined time. Therefore, our irradiator is entirely foolproof and it cannot occur that a careless or unskilled operator allows the electrodes to burn down to the sockets, a risk which is always present with electrodes arranged in parallel relation. As mentioned, one of the electrodes may be parallel to the optical axis of g' the reector, but still the other electrode is at an acute angle to the first electrode.

It is another object of our invention to provide a self-contained and readily portable unit on which all parts required for its operation are assembled.

To this end, We providea transformer on the irradiator and connect the transformer to a normal, preferably a. c., electric lighting system on the one hand, and to the electrodes on the other hand. By these means, notwithstanding the connection of the transformer to a normal system, so much energy is produced that the irradiator is Very efficient.

It is another object of our invention to produce a maximum illuminated area of practically uniform light intensity. To this end, we build up our reflector from a set of plane sector-shaped mirrors arranged concentrically to the optical axis of the reflector, and at an angle to each other.

By arranging one of the electrodes in parallel relation to, and at a short distance from, the optical axis of the reflector and the other at an acute angle to this electrode, uniform intensity of the illuminated area is obtained independently of the burning-down of the electrodes.

For the same purpose the mirrors of the reflector are made with non-reflecting areas, and the size of the areas is increased toward the reflector axis.

By these means, We obtain a readily portable and self-contained irradiator whose construction is so simple that it can be operated by non-skilled persons. It is understood that our invention is not limited to portable apparatus of the kind referred to, but may also be adapted to stationary irradiators if desired.

' In the accompanying drawings, a portable irradiator embodying our invention is illustrated more or less diagrammatically by way of example.

In the drawings Fig. 1 is a side elevation, partly broken and Fig. 2 is an end elevation of the irradiator, viewed from the left in Fig. 1.

Open,

Fig. 3 shows part of the irradiatorY in section on 40.

line III-III ln Fig. 2.

Fig. 4 is an elevation of an electrode for the irradiator, partly broken open to expose its core.

Fig. 5 is an end elevation, viewed as in Fig. 2, and Fig. 6 is a section on the line VI-VI in Fig. 5, 45 of a reflector whose mirrors define slots with sides diverging toward the optical axis of the reflector, and

Fig. '7 is an end elevation of ari/other reflector whose mirrors define holes whose size increases 50.;

toward the optical axis of the reflector.

Referring now to the drawings, l is the base, or transformer casing, of the irradiator, and I9 is a transformer in the casing, with a conduit 20 for connecting the primary coil of the transformer to a normal, for instance, 220 volt, lighting system.

A handle 4 for carrying the irradiator is secured to the top plate of the transformer casing I, and a pin 1 is inserted in a bore in the front portion 5 of handle 4, and held by a set screw 6. 'Ihe upper end of the pin has a fork 8 with a pivot 9, and a wing nut II on the pivot. A bracket I0 on a reflector casing 2 is inserted between the arms of the fork 8 and placed on the pivot 9.

At its outer end, the reflector casing 2 is open, so that atmospheric oxygen has free access to the arc between the electrodes 26 and 21, as against the closed-up air chamber referred to. On its upper portion, the reflector casing 2 is equipped with a ventilator I3 having slots I2. Hinged to its inner end at I4, and secured by a swing bolt I6, a nut I1, and a slotted member I8, is an electrode cowl 3. At its inner end, the cowl 3 is equipped with a dished bottom plate 22, preferably of heat-insulating material, with holes 23 through which the electrodes 26 and 21 project into the reilector casing 2. Secured on the bottom plate 22 is a frame 3' in the cowl 3. The holder 25 for the electrode 21 is secured on a flange 3" of the frame which projects through the lower hole 23. By these means, the electrode 21 is held in a ilxed position with respect to the reflectory 28 during the operation of the irradiator. The holder 24 for the electrode 26 is secured to an arm 29 which is fulcrumed at 29 in a bearing block 3| at the free end of a support whose members 3|] are laminated springs. The holders 24 and 25 are connected to the secondary coil of transformer I9 by conduits 2|.

The xed electrode 21 is arranged in parallel relation to, and at a short distance from, the optical axis of a reflector 28 in the casing 2. The reilector has an elongated aperture 41 so that the Yelectrodes 26 and 21 are free to move when the cowl 3 is turned about its hinge I4.

An arm 32 with a balance weight 32 at its free end, is secured to the holder arm 29, the balance weight being so determined that the weight of the electrode 26, its holder 24, and the arm 29, is only partly balanced.

The springs 30 have a certain initial tension which moves them against an adjustable stop- 36' in a bracket 38 below the springs 39. A shaft `4I), with a knurled handle 4I at its outer end, is

mounted to rotate in the frame 3. A cam 38 is secured on the shaft 49, and a spring 39 whose free end is connected to a short arm on the shaft 40, tends to turn the shaft anti-clockwise. An arm 33, with a sector 34 at its free end, is connected to the arms 29 and 32', and is supported by a brake block 36 at the end of a laminated spring 31 which, in turn, is supported by the cam 38.

In the position of parts illustrated in Fig. 3, the cam 38, through the means described, holds the spring frame 39 in elevated position and the free end of electrode 26 is at some distance from that of the fixed electrode 21. To strike the arc be- 1 tween the two electrodes, the handle 4IA is turned clockwise, the sector 34 is released by the brakey block 36, and the only partly balanced weight of the electrode 26 moves the end of this electrode against the end of electrode 21. The arc is now struck and then the handle is released to allow the cam and the brake block to again elevate the sector under the action of spring 39.

Referring now to Fig. 4, each electrode, for instance 26, as shown, has a hollow body of carbon, and a core 43. The core consists of one of the substances mentioned in the introduction, or a mixture of such substances, which produce a spectrum similar to the suns, and preferably the composition of the core 43 is such that ultraviolet rays are produced. The desirable current density of 0.26 amp. per square millimetre of electrode cross-section is obtained by suitable resistances, not shown.

As mentioned, the reflector should be so designed that a maximum illuminated area of practically uniform light intensity is obtained independently of the distance of the arc from the reiiector. To this end a reflector 50, as shown in Figs. 5 and 6, is built up from plane, sector-shaped mirrors arranged concentrically to the axis of the reflector, and at an angle to each other. As also mentioned, the mirrors 44 are made with non-reilecting areas. In the reflector 50, each mirror 44 has a slot 45 whose sides diverge toward the optical axis of the reflector.

The plane mirrors 44 make up together a hollow pyramid with the elongated aperture 41 a1- ready described with reference to the reflector 28 in Fig. 3.

Instead of providing diverging slots 45, as shown in Figs. 5 and 6, each mirror, as shown for the reflector 5I in Fig. 7, is provided with a set of radi-l ally arranged circular holes 46, whose diameter gradually increases toward the optical axis of thereflector.

It is understoodA that instead of providing slots,

or holes, in the individual mirrors 44, bodies of non-reilective material may be placed on the mirrors in any suitable way.

Preferably, the reflector should have 8 to 20 mirrors 44. The best effect is obtained with l2 mirrors. n Y

By providingv the means described on the mirrors, the amount of light reilected remains substantially constant notwithstanding the variable distance of the arc from the reilector as the electrodesv burn down.

We claim:

l. In a portable electric irradiator, a rellector including a set of plane sector-shaped mirrorsy arranged concentrically to the optical axis of the reilector and at an angle to each other, and defining eacha plurality of holes whose size increases toward the optical axis of the reilector, and a pair of electrodes extending through the reilector.

2. In a portable electric irradiator, a transformer casing, a transformerin the casing, a reilector casing adjustably mounted on the transformer casing, a reflector inthe reflector casing having an elongated aperture, an electrode cowl hinged,

to the reflector casing, a fixed electrodev secured in the cowl and extending through the elongated aperture in the reflector, a spring frame in the cowl, a movable electrode fulcrumed onv the spring ALBERT STAHN. THEODOR BORNEMANN. 

